tiramisu/tiramisu/value.py

# -*- coding: utf-8 -*-
"takes care of the option's values and multi values"
# Copyright (C) 2013 Team tiramisu (see AUTHORS for all contributors)
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# ____________________________________________________________
from time import time
from copy import copy
from tiramisu.error import ConfigError, SlaveError
from tiramisu.setting import owners, multitypes, expires_time, storage_type
from tiramisu.autolib import carry_out_calculation
from tiramisu.i18n import _
from tiramisu.option import SymLinkOption


class Values(object):
    """The `Config`'s root is indeed  in charge of the `Option()`'s values,
    but the values are physicaly located here, in `Values`, wich is also
    responsible of a caching utility.
    """
    __slots__ = ('context', '_p_')

    def __init__(self, context, storage):
        """
        Initializes the values's dict.

        :param context: the context is the home config's values

        """
        self.context = context
        # the storage type is dictionary or sqlite3
        import_lib = 'tiramisu.storage.{0}.value'.format(storage_type)
        self._p_ = __import__(import_lib, globals(), locals(), ['Values'],
                              -1).Values(storage)

    def _getkey(self, opt):
        """depends on the storage utility.
        typically, the option's path in the parent `Config` or `SubConfig`
        """
        if self._p_.key_is_path:
            return self._get_opt_path(opt)
        else:
            return opt

    def _getdefault(self, opt):
        """
        actually retrieves the default value

        :param opt: the `option.Option()` object
        """
        meta = self.context.cfgimpl_get_meta()
        if meta is not None:
            value = meta.cfgimpl_get_values()[opt]
        else:
            value = opt.impl_getdefault()
        if opt.impl_is_multi():
            return copy(value)
        else:
            return value

    def _getvalue(self, opt, validate=True):
        """actually retrieves the value

        :param opt: the `option.Option()` object
        :returns: the option's value (or the default value if not set)
        """
        key = self._getkey(opt)
        if not self._p_.hasvalue(key):
            # if there is no value
            value = self._getdefault(opt)
            if opt.impl_is_multi():
                value = Multi(value, self.context, opt, validate)
        else:
            # if there is a value
            value = self._p_.getvalue(key)
            if opt.impl_is_multi() and not isinstance(value, Multi):
                # load value so don't need to validate if is not a Multi
                value = Multi(value, self.context, opt, validate=False)
        return value

    def get_modified_values(self):
        return self._p_.get_modified_values()

    def __contains__(self, opt):
        """
        implements the 'in' keyword syntax in order provide a pythonic way
        to kow if an option have a value

        :param opt: the `option.Option()` object
        """
        return self._p_.hasvalue('value', self._getkey(opt))

    def __delitem__(self, opt):
        """overrides the builtins `del()` instructions"""
        self.reset(opt)

    def reset(self, opt):
        key = self._getkey(opt)
        if self._p_.hasvalue(key):
            setting = self.context.cfgimpl_get_settings()
            opt.impl_validate(opt.impl_getdefault(), self.context,
                              'validator' in setting)
            self.context.cfgimpl_reset_cache()
            if (opt.impl_is_multi() and
                    opt.impl_get_multitype() == multitypes.master):
                for slave in opt.impl_get_master_slaves():
                    self.reset(slave)
            self._p_.resetvalue(key)

    def _isempty(self, opt, value):
        "convenience method to know if an option is empty"
        empty = opt._empty
        if (not opt.impl_is_multi() and (value is None or value == empty)) or \
           (opt.impl_is_multi() and (value == [] or
                                     None in value or empty in value)):
            return True
        return False

    def _getcallback_value(self, opt, index=None):
        """
        retrieves a value for the options that have a callback

        :param opt: the `option.Option()` object
        :param index: if an option is multi, only calculates the nth value
        :type index: int
        :returns: a calculated value
        """
        callback, callback_params = opt._callback
        if callback_params is None:
            callback_params = {}
        return carry_out_calculation(opt._name, config=self.context,
                                     callback=callback,
                                     callback_params=callback_params,
                                     index=index)

    def __getitem__(self, opt):
        "enables us to use the pythonic dictionnary-like access to values"
        return self.getitem(opt)

    def getitem(self, opt, validate=True, force_permissive=False,
                force_properties=None, validate_properties=True):
        ntime = None
        key = self._getkey(opt)
        if self._p_.hascache('value', self._getkey(opt)):
            ntime = time()
            is_cached, value = self._p_.getcache('value', key, ntime)
            if is_cached:
                if opt.impl_is_multi() and not isinstance(value, Multi):
                    #load value so don't need to validate if is not a Multi
                    value = Multi(value, self.context, opt, validate=False)
                return value
        val = self._getitem(opt, validate, force_permissive, force_properties,
                            validate_properties)
        if 'expire' in self.context.cfgimpl_get_settings() and validate and \
                validate_properties and force_permissive is False and \
                force_properties is None:
            if ntime is None:
                ntime = time()
            self._p_.setcache('value', key, val, ntime + expires_time)

        return val

    def _getitem(self, opt, validate, force_permissive, force_properties,
                 validate_properties):
        # options with callbacks
        setting = self.context.cfgimpl_get_settings()
        is_frozen = 'frozen' in setting[opt]
        # if value is callback and is not set
        # or frozen with force_default_on_freeze
        if opt.impl_has_callback() and (
                self.is_default_owner(opt) or
                (is_frozen and 'force_default_on_freeze' in setting[opt])):
            no_value_slave = False
            if (opt.impl_is_multi() and
                    opt.impl_get_multitype() == multitypes.slave):
                masterp = self._get_opt_path(opt.impl_get_master_slaves())
                mastervalue = getattr(self.context, masterp)
                lenmaster = len(mastervalue)
                if lenmaster == 0:
                    value = []
                    no_value_slave = True

            if not no_value_slave:
                value = self._getcallback_value(opt)
                if (opt.impl_is_multi() and
                        opt.impl_get_multitype() == multitypes.slave):
                    if not isinstance(value, list):
                        value = [value for i in range(lenmaster)]
            if opt.impl_is_multi():
                value = Multi(value, self.context, opt, validate)
            # suppress value if already set
            self.reset(opt)
        # frozen and force default
        elif is_frozen and 'force_default_on_freeze' in setting[opt]:
            value = self._getdefault(opt)
            if opt.impl_is_multi():
                value = Multi(value, self.context, opt, validate)
        else:
            value = self._getvalue(opt, validate)
        if validate:
            opt.impl_validate(value, self.context, 'validator' in setting)
        if self.is_default_owner(opt) and \
                'force_store_value' in setting[opt]:
            self.setitem(opt, value, is_write=False)
        if validate_properties:
            setting.validate_properties(opt, False, False, value=value,
                                        force_permissive=force_permissive,
                                        force_properties=force_properties)
        return value

    def __setitem__(self, opt, value):
        self.setitem(opt, value)

    def setitem(self, opt, value, force_permissive=False, is_write=True):
        # is_write is, for example, used with "force_store_value"
        # user didn't change value, so not write
        # valid opt
        opt.impl_validate(value, self.context,
                          'validator' in self.context.cfgimpl_get_settings())
        if opt.impl_is_multi() and not isinstance(value, Multi):
            value = Multi(value, self.context, opt)
        self._setvalue(opt, value, force_permissive=force_permissive,
                       is_write=is_write)

    def _setvalue(self, opt, value, force_permissive=False,
                  force_properties=None,
                  is_write=True, validate_properties=True):
        self.context.cfgimpl_reset_cache()
        if validate_properties:
            setting = self.context.cfgimpl_get_settings()
            setting.validate_properties(opt, False, is_write,
                                        value=value,
                                        force_permissive=force_permissive,
                                        force_properties=force_properties)
        owner = self.context.cfgimpl_get_settings().getowner()
        self._p_.setvalue(self._getkey(opt), value, owner)

    def getowner(self, opt):
        """
        retrieves the option's owner

        :param opt: the `option.Option` object
        :returns: a `setting.owners.Owner` object
        """
        if isinstance(opt, SymLinkOption):
            opt = opt._opt
        owner = self._p_.getowner(self._getkey(opt), owners.default)
        meta = self.context.cfgimpl_get_meta()
        if owner is owners.default and meta is not None:
            owner = meta.cfgimpl_get_values().getowner(opt)
        return owner

    def setowner(self, opt, owner):
        """
        sets a owner to an option

        :param opt: the `option.Option` object
        :param owner: a valid owner, that is a `setting.owners.Owner` object
        """
        if not isinstance(owner, owners.Owner):
            raise TypeError(_("invalid generic owner {0}").format(str(owner)))
        if self.getowner(opt) == owners.default:
            raise ConfigError(_('no value for {0} cannot change owner to {1}'
                                '').format(opt._name, owner))
        self._p_.setowner(self._getkey(opt), owner)

    def is_default_owner(self, opt):
        """
        :param config: *must* be only the **parent** config
                       (not the toplevel config)
        :return: boolean
        """
        return self.getowner(opt) == owners.default

    def reset_cache(self, only_expired):
        """
        clears the cache if necessary
        """
        if only_expired:
            self._p_.reset_expired_cache('value', time())
        else:
            self._p_.reset_all_cache('value')

    def _get_opt_path(self, opt):
        """
        retrieve the option's path in the config

        :param opt: the `option.Option` object
        :returns: a string with points like "gc.dummy.my_option"
        """
        return self.context.cfgimpl_get_description().impl_get_path_by_opt(opt)

# ____________________________________________________________
# multi types


class Multi(list):
    """multi options values container
    that support item notation for the values of multi options"""
    __slots__ = ('opt', 'context')

    def __init__(self, value, context, opt, validate=True):
        """
        :param value: the Multi wraps a list value
        :param context: the home config that has the values
        :param opt: the option object that have this Multi value
        """
        self.opt = opt
        self.context = context
        if not isinstance(value, list):
            value = [value]
        if validate and self.opt.impl_get_multitype() == multitypes.slave:
            value = self._valid_slave(value)
        elif self.opt.impl_get_multitype() == multitypes.master:
            self._valid_master(value)
        super(Multi, self).__init__(value)

    def _valid_slave(self, value):
        #if slave, had values until master's one
        masterp = self.context.cfgimpl_get_description().impl_get_path_by_opt(
            self.opt.impl_get_master_slaves())
        mastervalue = getattr(self.context, masterp)
        masterlen = len(mastervalue)
        valuelen = len(value)
        if valuelen > masterlen or (valuelen < masterlen and
                                    not self.context.cfgimpl_get_values(
                                    ).is_default_owner(self.opt)):
            raise SlaveError(_("invalid len for the slave: {0}"
                               " which has {1} as master").format(
                                   self.opt._name, masterp))
        elif valuelen < masterlen:
            for num in range(0, masterlen - valuelen):
                value.append(self.opt.impl_getdefault_multi())
        #else: same len so do nothing
        return value

    def _valid_master(self, value):
        masterlen = len(value)
        values = self.context.cfgimpl_get_values()
        for slave in self.opt._master_slaves:
            if not values.is_default_owner(slave):
                value_slave = values._getvalue(slave)
                if len(value_slave) > masterlen:
                    raise SlaveError(_("invalid len for the master: {0}"
                                       " which has {1} as slave with"
                                       " greater len").format(
                                           self.opt._name, slave._name))
                elif len(value_slave) < masterlen:
                    for num in range(0, masterlen - len(value_slave)):
                        value_slave.append(slave.impl_getdefault_multi(),
                                           force=True)

    def __setitem__(self, key, value):
        self._validate(value)
        #assume not checking mandatory property
        super(Multi, self).__setitem__(key, value)
        self.context.cfgimpl_get_values()._setvalue(self.opt, self)

    def append(self, value, force=False):
        """the list value can be updated (appened)
        only if the option is a master
        """
        if not force:
            if self.opt.impl_get_multitype() == multitypes.slave:
                raise SlaveError(_("cannot append a value on a multi option {0}"
                                   " which is a slave").format(self.opt._name))
            elif self.opt.impl_get_multitype() == multitypes.master:
                values = self.context.cfgimpl_get_values()
                if value is None and self.opt.impl_has_callback():
                    value = values._getcallback_value(self.opt)
                    #Force None il return a list
                    if isinstance(value, list):
                        value = None
        self._validate(value)
        super(Multi, self).append(value)
        self.context.cfgimpl_get_values()._setvalue(self.opt, self, validate_properties=not force)
        if not force and self.opt.impl_get_multitype() == multitypes.master:
            for slave in self.opt.impl_get_master_slaves():
                if not values.is_default_owner(slave):
                    if slave.impl_has_callback():
                        index = self.__len__() - 1
                        dvalue = values._getcallback_value(slave, index=index)
                    else:
                        dvalue = slave.impl_getdefault_multi()
                    old_value = values.getitem(slave, validate_properties=False)
                    if len(old_value) < self.__len__():
                        values.getitem(slave, validate_properties=False).append(
                            dvalue, force=True)
                    else:
                        values.getitem(slave, validate_properties=False)[index] = dvalue

    def sort(self, cmp=None, key=None, reverse=False):
        if self.opt.impl_get_multitype() in [multitypes.slave,
                                             multitypes.master]:
            raise SlaveError(_("cannot sort multi option {0} if master or slave"
                               "").format(self.opt._name))
        super(Multi, self).sort(cmp=cmp, key=key, reverse=reverse)
        self.context.cfgimpl_get_values()._setvalue(self.opt, self)

    def reverse(self):
        if self.opt.impl_get_multitype() in [multitypes.slave,
                                             multitypes.master]:
            raise SlaveError(_("cannot reverse multi option {0} if master or "
                               "slave").format(self.opt._name))
        super(Multi, self).reverse()
        self.context.cfgimpl_get_values()._setvalue(self.opt, self)

    def insert(self, index, obj):
        if self.opt.impl_get_multitype() in [multitypes.slave,
                                             multitypes.master]:
            raise SlaveError(_("cannot insert multi option {0} if master or "
                               "slave").format(self.opt._name))
        super(Multi, self).insert(index, obj)
        self.context.cfgimpl_get_values()._setvalue(self.opt, self)

    def extend(self, iterable):
        if self.opt.impl_get_multitype() in [multitypes.slave,
                                             multitypes.master]:
            raise SlaveError(_("cannot extend multi option {0} if master or "
                               "slave").format(self.opt._name))
        super(Multi, self).extend(iterable)
        self.context.cfgimpl_get_values()._setvalue(self.opt, self)

    def _validate(self, value):
        if value is not None:
            try:
                self.opt._validate(value)
            except ValueError, err:
                raise ValueError(_("invalid value {0} "
                                   "for option {1}: {2}"
                                   "").format(str(value),
                                              self.opt._name, err))

    def pop(self, key, force=False):
        """the list value can be updated (poped)
        only if the option is a master

        :param key: index of the element to pop
        :return: the requested element
        """
        if not force:
            if self.opt.impl_get_multitype() == multitypes.slave:
                raise SlaveError(_("cannot pop a value on a multi option {0}"
                                   " which is a slave").format(self.opt._name))
            elif self.opt.impl_get_multitype() == multitypes.master:
                for slave in self.opt.impl_get_master_slaves():
                    values = self.context.cfgimpl_get_values()
                    if not values.is_default_owner(slave):
                        #get multi without valid properties
                        values.getitem(slave,
                                       validate_properties=False
                                       ).pop(key, force=True)
        #set value without valid properties
        ret = super(Multi, self).pop(key)
        self.context.cfgimpl_get_values()._setvalue(self.opt, self, validate_properties=not force)
        return ret